Optimal Principle on Composition of B Site Elements in Perovskite Electrodes with Sr at A Site for Solid Oxide Fuel Cell

Based on ab inito method, the binding energies of SrBO3 perovskite type electrode materials in solid oxide fuel cell in which B site chosen from 3rd to 6th periods elements were calculated. Effect of elements used in B site on the formation of cubic or hexagonal crystal structure was discussed. Structure stability diagram that contained three phases (unstable, cubic stable and hexagonal stable phases) was achieved. The distribution rule of composition points in this diagram was confirmed by inducing radius and valence data of cations at B site as validation data. Besides, there being plenty of experimental materials data in literature was introduced to this structure stability diagram, according to their compositions and lever rule. Distribution area of the obtained data was analysed and the results locate quite concentrated, indicating that the optimized area is centered by along the Mo-Fe-Co line. Within this area, our calculations find that formation energy and migration energy of oxygen vacancy as well as the band gap of the materials are suitable to be used as electrode materials in solid oxide fuel cell. The optimization area in SrBO3 structure stability diagram can provide meaningful guidance for material selection.